This invention relates to radiation curable coating compositions which when cured form highly abrasion resistant coatings for most any susbtrate.
In the past, many curable or crosslinkable compositions have been developed in the art for use as coatings for clear plastics and the like which when cured offer varying degrees of abrasion and solvent resistance. Among such compositions are fluorocarbon-vinyl ether copolymers crosslinked with polysilicic acid, melamine-formaldehyde coatings, polyurethanes, polysiloxanes, polyakyls, polyallyldicarbonates, and polyfunctional acrylics. Such coatings have been applied to a wide variety of polymeric substrates including acrylic sheeting, polycarbonates, polyesters and the like. These compositions are generally applied to the substrate by any known method such as dipping, brushing or spraying and are cured at either high temperature or at low temperature in the presence of a catalyst. Ultraviolet curable coatings based on unsaturated polyester resins, including polyacrylics, and containing a photoinitiator have also been described in the art.
The present invention deals with radiation curable coating compositions containing a specific class of polyacrylates and cellulose esters which can be applied to a variety of substrates. The precured coatings are dust-free, level out extremely well on the substrates and are stable against air inhibition of cure such that they can be cured in air hours after application to the substrate. On curing, coatings are formed exhibiting extremely high abrasion resistance, flexibility, weatherability and resistance to thermal stress cracking. Such coatings are additionally scratch resistant and are not attacked by chemical or organic solvents.